Polymerization of unsaturated organic compounds by peroxides is well known in polymer synthesis. The small unsaturated organic molecules are the monomers which are polymerized to produce many various plastic products. Among those monomers are ethylene, propylene, styrene, .alpha.-methyl styrene, vinyl toluene, vinyl ethers, and vinyl esters.
Peroxides have been used for many years to crosslink rubber compositions, however they have not found general use in the tire industry. Among the concerns that the tire industry has about the use of peroxides, some of these concerns relate to the radical mechanism of peroxide crosslinking and to the structure of the crosslink. Compositions cured with peroxides are thought to have shorter crosslinks which are less flexible than comparable crosslinks from sulfur-cured compositions and therefore peroxide-cured compositions are believed to exhibit less resistance to abrasion and cut growth. Also, peroxides are believed in the tire industry to be more sensitive to compounding ingredients and therefore, designing a peroxide compound would limit the flexibility available in a sulfur-cure system.